<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        @import url('https://fonts.googleapis.com/css?family=Exo:400,700');

        * {
            margin: 0px;
            padding: 0px;
        }

        body {
            font-family: 'Exo', sans-serif;
        }


        .context {
            width: 100%;
            position: absolute;
            top: 50vh;

        }

        .context h1 {
            text-align: center;
            color: #fff;
            font-size: 50px;
        }


        .area {
            background: #4e54c8;
            background: -webkit-linear-gradient(to left, #8f94fb, #4e54c8);
            width: 100%;
            height: 100vh;


        }

        .circles {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            overflow: hidden;
        }

        .circles li {
            position: absolute;
            display: block;
            list-style: none;
            width: 20px;
            height: 20px;
            background: rgba(255, 255, 255, 0.2);
            animation: animate 25s linear infinite;
            bottom: -150px;

        }

        .circles li:nth-child(1) {
            left: 25%;
            width: 80px;
            height: 80px;
            animation-delay: 0s;
        }


        .circles li:nth-child(2) {
            left: 10%;
            width: 20px;
            height: 20px;
            animation-delay: 2s;
            animation-duration: 12s;
        }

        .circles li:nth-child(3) {
            left: 70%;
            width: 20px;
            height: 20px;
            animation-delay: 4s;
        }

        .circles li:nth-child(4) {
            left: 40%;
            width: 60px;
            height: 60px;
            animation-delay: 0s;
            animation-duration: 18s;
        }

        .circles li:nth-child(5) {
            left: 65%;
            width: 20px;
            height: 20px;
            animation-delay: 0s;
        }

        .circles li:nth-child(6) {
            left: 75%;
            width: 110px;
            height: 110px;
            animation-delay: 3s;
        }

        .circles li:nth-child(7) {
            left: 35%;
            width: 150px;
            height: 150px;
            animation-delay: 7s;
        }

        .circles li:nth-child(8) {
            left: 50%;
            width: 25px;
            height: 25px;
            animation-delay: 15s;
            animation-duration: 45s;
        }

        .circles li:nth-child(9) {
            left: 20%;
            width: 15px;
            height: 15px;
            animation-delay: 2s;
            animation-duration: 35s;
        }

        .circles li:nth-child(10) {
            left: 85%;
            width: 150px;
            height: 150px;
            animation-delay: 0s;
            animation-duration: 11s;
        }



        @keyframes animate {

            0% {
                transform: translateY(0) rotate(0deg);
                opacity: 1;
                border-radius: 0;
            }

            100% {
                transform: translateY(-1000px) rotate(720deg);
                opacity: 0;
                border-radius: 50%;
            }

        }
    </style>
</head>

<body>
    <div class="context">
        <h1>Pure Css Animated Background</h1>
    </div>


    <div class="area">
        <ul class="circles">
            <li></li>
            <li></li>
            <li></li>
            <li></li>
            <li></li>
            <li></li>
            <li></li>
            <li></li>
            <li></li>
            <li></li>
        </ul>
    </div>
</body>

</html>